Compliant joints, or flexures, gain their motion through the deflection of the joint material, rather than multiple joint surfaces rotating and/or sliding relative to each other. Because compliant joints are monolithic they have no backlash from joint clearances or friction from contacting surfaces. Energy is stored in the material as the joint flexes. This energy can then be used advantageously by designing the joint to exhibit desired force-deflection characteristics without additional springs.
Compliant joints are often used when creating multi-stable mechanisms capable of having two or more equilibrium positions. Although compliant joints exhibit many benefits, they are often limited in their range of motion, and are generally harder to design, than their rigid-body counterparts, due to the coupled motion and energy equations that govern their behavior.
Compliant mechanisms manufactured from sheet goods with motion out of the plane of manufacture have been classified as “lamina emergent mechanisms” (LEMs). While much work has been done in developing such compliant joints for micro and macro applications, prior solutions often exhibit a number of problematic attributes.